Local buckling and concrete confinement of concrete-filled box coulmns with HT690 steel under axial Compression

• Main Authors: CHUN-YUNG LO, 羅俊詠
• Other Authors: Cheng-Cheng Chen
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/86200190698893601883

碩士 === 國立臺灣科技大學 === 營建工程系 === 102 === The main purposes of this research are to investigate the local buckling of CFBC with high Performance Steel (HT690) and the concrete confinement development process and mechanism of concrete-filled box columns with various cross-section aspect ratio. The axial behavior of the CFBC was simulated by using a commercial finite element program ABAQUS. The feasibility of the finite element models was verified by comparing the finite element analysis results to the experimental results. Based on FEM simulation results, the following conclusions can be drawn: (1) The strength of CFBC specimens decrease rapidly after the first peak strength is reached. This phenomenon is mainly due to the strength drop of concrete when concrete crushed. The higher the b/t ratio of the column plate was, the faster the strength degradation resulted. (2) Concrete confinement provided by horizontal arch action starts to become noticeable after concrete crushing. Vertical arch action, which provides additional concrete confinement, is developed after column wall buckling. Horizontal arch action combined with vertical arch action provides significant confinement to the concrete, and as a result, concrete started to gain its strength. A larger column plate b/t ratio resulted in an earlier development of vertical arch action. (3) The larger the cross-section aspect ratio was, the less effective the horizontal and vertical arch actions were. It is predicted that this factor will reduce the flexural ductility of CFBC, especially when the column is subjected to weak axis moment.